This invention relates to a knife holder for a log slabbing chipper and other wood cutting machines such as lumber edging chippers.
In conventional practice, chipper knives are secured in a rotor head by clamp plates secured by screws perpendicular to the knife blade. This mounting arrangement requires deep slots in the knives to receive the clamp screws since the position of the knife varies in relation to the clamp screws as the knife becomes narrower from repeated sharpening. The slots complicate the manufacture of the knives, reduce the strength of the knives, introduce undesirable stresses in heat treating and reduce the service life of the knives by limiting the number of times they may be re-sharpened.
Also, the conventional knife clamping arrangements require a high degree of dimensional accuracy for positive positioning of the interfitting parts and provide inadequate support for the knife, resulting in frequent breakage. These deficiencies also often result in damage to the knife holder as well as the knife, thereby further increasing the maintenance cost of the machine.
My U.S. Pat. No. 3,777,793 discloses an improved knife and knife holder which overcome the foregoing disadvantages. The present invention relates to further improvements having additional features and advantages as set forth below.
Objects of the present invention are, therefore, to provide an improved knife holder in a log slabbing chipper or other wood cutting machine, to provide a knife holder which provides better support for the knife, to provide a knife holder which reduces breakage of both knives and holders, to provide a knife holder which will increase the service life of the knife to provide a knife holder adapted to receive unslotted knives, to provide a knife holder of more simple construction which requires less precision in its manufacture, is easier to maintain and adjust, requires less time for knife changing and offers less resistance to material flowing through the knife holder, and which has clamp screws accessible to impact or power wrenches.